Relay



C. H. LARSON July 24, 1934.

RELAY Filed J'uly 5, 19:52

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Patented July 24, 1934 I reame RELAY Carl E. Larson, Elkhart, llnd., assignor to -Adlake Company, Elkhart, Ind., a corporation of Illinois .Annotation July 5, 1932, serial Nn. 620,77@

1s claims. (ci. 20o-97) The principal object of this invention vis to provide a mercury switohrelay that will delay opening a circuitfor a selected'period after the armature has been raised, andwill close thatc Signaling Principles and Practiceschapter 10, f

y pages 29 to 30, publishedby the Signal Section 'considerable v'distance into the envelope, and is,

' American Railway Association. 13o-Vescy Street,

New York, New York. g

i Fig. 1 is a vertical-sectionthrough a back contact relay, sho l the-partsin closed circuit position; 'Q-

Fig. 2 is a s lrszectio'ii,'showing theparts just after the magnethas been energized and the 2 displacer raisedybut before the circuit has .been

' broken;

f ',Fig. 3 'is a broken; t

. Fig. 4 is a perspective view ofthe upper portion of the displacerjv y'and Fig. 5'is asectional, view through the upper portion of a modied form of displacer.

But the drawing andthe correspondingly specinc description are used for'the purpose f illustration and disclosure only, and are not intended 0 to-define the scope' of the claims.

\ The glass envelope 10 is a-cylinder sealed od at the top at 11, and having a ilat base 12 at the bottom, in'which latter lead-in conductors 1'3 and 14 are sealed. The conductor 13 projects a surrounded by'a glass sleeve 15, fused to the base 12. The conductors are equipped with suitableA terminals 16 and 17, respectively. y A

Within the envelope is a charge of mercury Y18, a displacer 19, springs'20 to protect the envelope from the displacer, and a gas ll of helium, hy

drogen, or the like. The displacer 19 is made of Swedish iron, on account of its highpermeability and low residualmagnetism, but, o f course, 5 may be made of other iron or other vmagnetic material. It israised from the positionshown in Fig. 1 to that shown in Figs. 2.and 3 by an electromagnet comprising a solenoid 21, wound on a spool 22. l

The envelope 10 is loosely fitted in soft iron sleeves 23 and 24, clamped by clips 25 to'a yoke 26 of laminated iron. The envelope is held in adjusted position by the friction of a coil spring 27 of non-magnetic wire, such as phosphor bronze, wound tightly on the envelope and bearsimilar '-vew, showing thecircuit Elst ing against the adjacent ends of the sleeves 23 and 24.

Externally the displacer is a plain cylinder with narrow anges 28 at its top and bottom,

recessed at 29 to permit free flow of gas or mercury. Internally the displacer is also a simple cylinder for the major portion of its length, indicated bythe bore 30. Above this it is modied to provide a vent for allowing gas to escape rapidly, andalso a small or narrowbore for allowing gas .to enter slowly.

Inyth'especic construction the bit insertedfrom the bottom' iswithdrawn and entered from the4 top, leaving a partitionl which is later .m drilled to a smaller diameter 32. Above the parvtitionisa mass of burnt asbestos ber 33, clean hair, s'teel'wool, or the like, and above this is a meta1'ringf34, having a flaring seat 35, below which isashort cylindrical bore 36. :Thewall ofjthecylinder opposite the asbestos, or the'like,. has a, small ,or narrow bore 37x.

y Operation Assuming the parts'to'be in the position shown in Fig, v1; when theelectromagnet is energized the vdisplacer moves to close the gap between the adiacenti'v ends of the sleeves 23 and 24, andassumestheposition substantially'as shown inFig, .2.H A globule or -meniscus of mercury 38, resting on the seatl V35, excludes the ingress of gas except as it can slowly pass through-the small or narrow opening 37; lhence mercury is drawn up from below, as indicated at 39 (Fig. 2), maintaining the circuit between the electrodes 16 andv 17 closed by the-mercury. However, in time sufllcient gas-will veriter the bore of displacer to relieve the partial-yvacuum, and the mercury will descend totheposition shown inFlg. 3, where the circuit isiopen.` f

Upon deenergizing the magnet the will immediatelydrop to the position shown in Fig. 1', by .its own weight. At the outset this movement :will increasegthe pressure of the gas within the displacer above' the mercury, whichdisplacer v will rush easily through the asbestos and pass 'straining it from entering the top of the dis- 110' lio i tendency there is for the mercury globule to be f sucked down. Providing ridges on the seat as shown at lll in Fig. 3, reduces the tendency of the mercury to be drawn downwardly.

Thev small. or narrow bore 37 may be vplaced anywhere above the mercury level in the enjvelope, butl preferably isf entered opposite the asbestos or other ber, because that material acts as a filter in restraining vapor particles, whichl rise after the circuit is broken and have a tendj ency toA collect around` any opening and'vary the 1 ow'through it. The asbestos 'seems to collect v these vaporparticles at or'near its lower surface Vand thus maintain the flow through the opening 37 practically uniform.

The.r check valve arrangement employing a Vmercury seal is particularly noteworthy because vit is virtually impossible to obtain a hermetic ,seal by the use. of a4 solid ball such as rubber lor -metal,' inasmuch as thev gas pressureddiierentials are comparatively small. The inability to vproduce a solid ball ofinetal' or other 'material havingexact roundness also renders theuse of such a check valve impractical for sealing gas.

The time delay may be varied quite widely by changing the proportions. Also by adjusting the envelope with'respect to the magnet. In one form' that has vbeen found very satisfactory the displacer has a Ai inch external diameter anda inch internaldiameten The bore 32r is 1;/3 of an inch in diameter; the ring 34is 532 Tof an inch in vertical dimension; the iiare 35 is at an angle of forty-'five degrees, and the open-4 ing 36 is of -an inch in `diameter. The cylindrical bore below the ring isgf-of an inch long. The small opening 37 is l/ 1000 of an inch in diameter, and the time delay is approximately ten seconds, with the envelope and magnet in substantially the position as shown vin the drawing.

Although the invention has beenshown 'applied to a back contact relay, it is obvious that it is" equallyapplicable to a front contact relay, in which the electrodes are disconnected when the` coil is de-energized, but are bridged with mercury when the displacer is lowered.v by magnetic' ttraction.v 5 l I claim as my inventionr v v l. In a relay, a ysealed envelope containing' electrodes, which, when electrically '.connected, close an electrical circuit, a charge of liquid, a

- gas ll, and a displacer includinga` hollow4 body.

presenting a.' wide bottom openingto the liquid andl 'a narrow opening' to thej gas, the' Vdisplaceralso having a gas vent, and acheck valve controlling the vent wherebyliquid is allowed to Ienter the displacer rapidly and gasis restricted to yslow entry but allowedto escape rapidly .fromthe displacer, said-electrodes being arranged so that the' condition o f'the circuit isJ determined- 'ht h1' i withinthedislcer".l

by the belg of t e' mu d p a' in the envelopea gas ll, a mercury 4illl adapted' withl respect to -a fixed point on the envelope. v

2. Ina relay, a sealed envelope containing electrodes, which, when electrically connected, close an electrical circuit, a charge of liquid, a gas ll, and a displacer including a hollow body having a wide bottom opening to allow. free entrance and exit to liquid, a narrow upper openlcury and equipped with means for passing gas `spaced electrodesin .thegenvelopa a gas ll, a. l quantity oizmercury in the envelope adapted to Vdisplacer presenting a .relatively large opening to containing electrodes lwhich, when electrically connected, close an electrical circuit, a charge o f mercury, a gas ll, and a displacer comprising lazhollow body having a wide bottom opening to allow free iiow of mercury Ainto the body, and a vent permitting free iiow o f gas out of the i body whereby the body may readily descend into the mercury, said body also'having a restricted opening forgas to enter the `body and being provided with a mercury valve to check the entrance of gas through the vent, the electrodes being so arranged that the condition of the circuit is determined by the height of the liquidv Within the displacer with respect to a xed point on the envelope. v

4. In a mercuryv switch relay, a sealed envelope containing electrodes, a charge of mercury, a gas ll, and a displacer comprising a hollow body having a wide bottom opening to allow free flow of mercury into thebody, and anarrow opening -above the mercury level to allow re'-' quantity of mercury in the envelope adapted to be manipulated to make or break an electrical circuit through the electrodes, a hollow body. presenting a relatively large opening to the merrapidly through the upper. portion ofthe body in-one direction, but slowly in the other direction, whereby the movement of mercuryin the body is retarded in one direction only, said electrodes'being arranged so that the condition of the circuit is determined by the height of .the

point on theenvelop'e.

' 6. In Ia-mercury switch, a switch envelope,

be manipulated to make or break an electrical circuit, througnthe e1ectr0aesal displacerror mercury within the body vwith respect to la xed j changing themercury level in vthe envelope, saidl I the mercury and being -equippedwith means `for permitting a freeescape'of gas from the displacer but a slow admittance of gas to the displacer lwhenthe large-opening closed by mercury,

whereby the movement of mercury within the vdisplacer 'is retarded when receding only.. said electrodes being arranged so that the-"condition of the circuit is determined' bythe height of the i mercury within the' displacer 'respecttoa xed point on the envelope. '7. For use with af relay coil, -acircuitbreaker r'comprising a switch envelope, spaced 'electrodes to make vor break an electrical circuit, according to its levelfav displacer movable within the en velo'pev in responseto the coil for changingthe mercury level, and means for effecting vunequal time delays for making and breaking the electri.

calcircuit, said means'A including a valve seat,`a 15 1,967,948 porous packing beneath the seat, and a. globule ,y

of mercury resting on the seat.

8. In a mercury switch, a switch envelope, spaced electrodes in the envelope, a gas lill, a quantity of mercury in the envelope adapted to be manipulated to make or break an electrical circuit through the electrodes, a hollow body telescoped over one of the electrodes and presenting a relatively large opening to the mercury, and means associated with the body for permitting gas to pass through the upper portion of the body more rapidly in one direction than in the other whereby movement of mercury within,

the body to and from the said electrode is timed accordingly.

9. In a mercury switch, a switch envelope,

spaced electrodes in the envelope, a gas lill, a

quantity of mercury in the envolope adapted tospaced electrodes in the envelope, a gas ll, a

quantity of mercury in the envelope adapted to be manipulated to make or break an electrical circuit through the electrodes, a hollow body telescoped over one of the electrodes and presenting a relatively large opening to the mercury and a` relatively small opening to the gas, and a check valve associated with the body to permit a free f passage of gas in one direction only, said check valve including a valve seat, a globule of mer,- cury on the seat, and means for preventing the globule from being drawn through the seat.

11. In a relay including a c'oil, a switch envelope, spaced electrodes in the envelope, a gas ll, a charge ,of mercury adapted to make or break a circuit through the electrodes according to itslevel, a displacer responsive to the coil for changing the mercury level, said displacer presenting a wide opening to the mercury and a rel` ltion only, said check valve including a. valve seat;

atively small opening to the gas when the former is submerged in the mercury, and a check valve associated with the displacer for permitting free passage` of gas through the displacer in one dlv rection only, saidelectrodes being arranged so that the condition of the circuit is determined by the height of the mercury level within the dis- Y placer with respect to a fixed point on the envelope.

l2. In a relay including a coil, ak switch envelope, spaced electrodes in the envelope, a gas ll, a charge of mercury adapted to make or break a circuit through the electrodes according to its level, a displacer responsive to the coil for changing the mercury level, said displacer presenting a wide opening to the mercury and a relatively small opening to the gas when the former is submerged in the mercury, and a check valve associated with the displacer for allowing a trodes being arranged so that the condition of the circuit is determined by the height of the mercury level within the displacer with respect to a fixed point on the envelope.

13. In a relay including a coil, a switch envelope, spaced electrodes in the envelope, a gas ll, a charge of mercury adapted to make or break a circuit through the electrodes according to its level, a displacer responsive to the coil for changing the mercury level, said displacer presenting a wide opening to the mercury and a relatively H `,small opening to the gas when the former is submerged in the mercury, and a check valve associated with the displacer for permitting free pas--V sage of gas through the displacer in one direc-l a. globule of mercury resting on the seat, and means I or preventing the globule from being drawn through the seat.

CARL H. LAnsoN. 12o 

